title: Diagnostic accuracy of 18F choline PET/CT using time-of-flight reconstruction algorithm in prostate cancer patients with biochemical recurrence.
abstract: OBJECTIVE
  Image quality (IQ) of PET in voluminous body regions can be limited, which impairs the assessment of small metastatic lesions. Time-of-flight (TOF) reconstruction algorithm may deliver an increase of spatial resolution. The purpose of this study was to evaluate the impact of TOF on IQ, lesion detection rate, lesion volume (V) and SUVmax in F choline PET/CT of prostate cancer patients with biochemical recurrence compared to standard PET/CT reconstruction (standard).
  
  
  METHODS
  During a period of 9 months, 32 patients with prostate cancer (mean [SD] age, 71 [7.8] years) and biochemical recurrence were included in this prospective institutional review board-approved study. Each patient underwent a state-of-the-art 3-dimensional F choline PET/CT. A total of 76 lesions were assessed by 2 board-certified nuclear medicine physicians and a third-year resident. Lesion volume and SUVmax of local recurrence, lymph nodes, and organ metastases were compared between TOF and standard. Image quality and lesion demarcation were rated according to a 5-point Likert-type scale. Interobserver agreement was assessed.
  
  
  RESULTS
  Eight additional lesions were detected using TOF (SUVmax, 3.64 [0.95]; V, 0.58 cm [0.50]). Image quality was reduced (IQ standard, 1.28; TOF, 1.77; P < 0.01) in calculated TOF images, although quality of lesion demarcation was improved (lesion demarcation: standard, 1.66; TOF, 1.26; P < 0.01). SUVmax was significantly increased in TOF images (SUVmax standard, 6.9 [4.1]; TOF, 8.1 [4.1]; P < 0.01), whereas V did not show significant differences (V standard, 5.3 [10.4] cm; TOF, 5.4 [10.3] cm; P = 0.41). Interobserver agreement was good for combined ratings (1 + 2 and 3 + 4).
  
  
  CONCLUSIONS
  Application of TOF seems to be of additional value to detect small metastatic lesions in patients with prostate cancer and biochemical recurrence, which may have further clinical implications for secondary treatment.
authors.affiliation: From the *Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; †CDPI Clinics-Abdominal and Pelvic Imaging, Rio de Janeiro Federal University, Rio de Janeiro, Brazil; ‡Institute of Medical Statistics; and §Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hausmann
authors.forename: Leonardo K
authors.initials: LK
authors.lastname: Bittencourt
authors.forename: Ulrike I
authors.initials: UI
authors.lastname: Attenberger
authors.forename: Metin
authors.initials: M
authors.lastname: Sertdemir
authors.forename: Anja
authors.initials: A
authors.lastname: Weidner
authors.forename: Karen A
authors.initials: KA
authors.lastname: Büsing
authors.forename: Joachim
authors.initials: J
authors.lastname: Brade
authors.forename: Frederik
authors.initials: F
authors.lastname: Wenz
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: Dietmar J
authors.initials: DJ
authors.lastname: Dinter
mesh_terms: D000465:Algorithms; D002794:Choline / Q000031:analogs & derivatives*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D015588:Observer Variation; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: C516370:fluoromethylcholine; D002794:Choline